FGFR2 promotes resistance to ALK tyrosine kinase inhibitors and its inhibition acts synergistically with lorlatinib in the treatment of ALK-expressing neuroblastoma

Anaplastic Lymphoma Kinase inhibitors (ALK TKIs) are approved for the treatment of ALK-positive non-small cell lung cancer (NSCLC) and are in clinical trial for ALK-aberrant high-risk neuroblastoma (NB) patients, particularly loratinib. However, resistance to ALK inhibitors can occur in patients, via the activation of bypass-signalling pathways, and there is a need to identify these mechanisms as well as drugs that inhibit them to design therapeutic approaches that prevent resistance, and to treat ALK TKI relapsed/refractory disease. Using genome-wide CRISPR-Cas9 overexpression screens, we identified and validated FGFR2 as a desensitizer to lorlatinib in aberrant ALK-expressing high-risk NB. FGFR2 and FGFR2-associated pathways are up-regulated in lorlatinib-resistant NB cells. Moreover, high-throughput screens using a library of 1,430 FDA approved drugs identified kinase inhibitors including those targeting FGFR2 as efficacious in reducing the survival of lorlatinib resistant NB cells. Hence, the FGFR pathway was investigated as a therapeutic target applying the pan-FGFR inhibitor erdafitinib or the multi-kinase inhibitor ponatinib, resulting in reduced survival of lorlatinib-resitant cells in comparison to their lorlatinib-sensitive counterparts. Moreover, both FGFR inhibitors act synergistically with lorlatinib in vitro and in vivo, using patient-derived xenografts (PDXs) and genetically engineered models (GEMM) of ALK-expressing NB. FGFR2 mRNA expression also correlate with a poorer prognosis for NB patients, regardless of sub-type, suggesting that a broader range of patients may benefit from FGFR inhibitors. Overall, our data suggests that FGFR2 potentially plays roles in lorlatinib resistance in NB and that combined pharmacological inhibition of ALK and FGFR constitutes a therapeutic approach to treat high-risk NB.